Emulsion aggregation (EA) is a process for preparing toner. EA toners may be used in forming print and/or xerographic images. EA techniques may involve the formation of an emulsion latex of the resin particles by heating the resin using a batch. semi-continuous or continuous emulsion polymerization, as disclosed in, for example, U.S. Pat. No. 5,853,943, the disclosure of which hereby is incorporated by reference in entirety. Other examples of EA/coalescing processes for preparing toners are illustrated in U.S. Pat. Nos. 5,902,710; 5,910,387; 5,916,725 5,919,595; 5,925,488, 5,977,210, 5,994,020, and U.S. Publ. No. 2008/01017989 the disclosure of each of which hereby is incorporated by reference in entirety.
Polyester EA ultra low melt (ULM) toners have been prepared utilizing amorphous and crystalline polyester resins as illustrated, for example, in U.S. Publ. No. 2008/0153027, the disclosure of which hereby is incorporated by reference in entirety. The incorporation of the polyesters into the toner generally requires formulation into latex emulsions prepared by solvent in batch processes, for example, solvent flash emulsification and/or solvent-based phase inversion emulsification (PIE), which are time-consuming and energy-consuming.
In PIE, polyester resins are formed by dissolving a polyester resin in at least one organic solvent which then is removed, sometimes referred to as stripped, via a vacuum distillation process using a tube condenser resulting in an aqueous dispersion of resin particles. However, that is a slow process which typically takes about 14-16 hours to reach the specification of total residual solvents of <150 ppm for toner applications.
Accordingly, it would be advantageous to provide a process for the preparation of a polyester dispersion suitable for use in a toner product that is more efficient, takes less time, and results in a consistent toner product.